BBC Horizon Sugar v Fat Documentary: My Thoughts

To answer the hottest question in nutrition, twin doctors Chris and Xand Van Tulleken go on month long high-fat and high-sugar diets. The effects on their bodies are shocking and surprising.

So which is worse? Fat or sugar?

The show’s conclusion: Neither. But the 50:50 combination of fat and sugar (that is not found in nature but only in processed foods) is hard to resist and probably a big factor in the obesity epidemic.

My thoughts:

1. Even Bad Diets Work, But Not in a Good Way.

The high fat diet that one of the brothers went on, meant he couldn’t have any carbs. The high sugar diet that the other brother went on, meant avoiding fats. Despite eating as much as they could, both twins lost weight. Why?

Because when you exclude whole categories of foods, your choices are limited. You end up eating less.

This is the principle behind many of the most popular fad diets.

And this is why a chocolate sundae diet (where you can only eat chocolate sundaes), a hamburger diet or even a deep-fried Mars Bar diet would make you lose weight. If you can only eat chocolate sundaes, you can’t eat anything else, so you end up eating less.

Of course a chocolate sundae diet would be dreadfully unhealthy and pretty unpleasant after a while (how many sundaes could you eat before you got sick of them?).

2. The Usual Conclusion

When most people watch a programme like this, they are fascinated with the science but they ALSO want some kind of recommendation to use in their lives.

This put the makers of the programme in an awkward position. The focus of the programme was fat v sugar, which I think they answered quite well. But when it came time to give a take-home point, they had pretty much run out of time, and had to revert to the usual, state-the-obvious advice.

That’s why the nutrition professor’s advice was:“cutting out some of those discretionary treat type foods”
Note she said “some”.

But one of the twins later interpreted that as:“So Im going to cut those out completely“

And so the take-home message was “eat less processed food (or none at all)”.

Of course, for anyone who wants to lose weight it’s pretty clear what’s wrong with this advice.

It’s not groundbreaking to tell an overweight person that they should cut down the number of donuts, ice creams and cheesecakes they eat.

If it was as easy as just being told to stop eating processed foods, then our society wouldn’t have an obesity problem.

Of course, we know what we need to do. But HOW do you do make sure it happens?

Again, I don’t blame the documentary-makers, because it wasn’t the focus of the programme. But it shows that a lot of health advice focuses on the wrong thing: You can talk a lot about what you should and shouldn’t eat, but most people know what they should do, they just don’t know how to apply it to their life.

The Missing Advice

As the twins said in the documentary, there is no magic solution to losing weight. But one absolutely crucial fact is that if you don’t focus on changing behaviour you’re going to struggle.

I work exclusively with women over 40 (to help them lose weight using a behavioural programme), but here’s some advice that can be applied to anyone. Think of them as general principles for changing behaviour for weight loss.

1. Keep a food diary

Much of our eating is based on habit. A core part of getting back in control of your eating is to increase the awareness of what you’re eating and why you’re eating it. Ask what function does a particular food provide in your life. Are you eating it for hunger, for enjoyment or for other reasons?

The easiest way to increase awareness is to keep a food diary. There’s a lot of research that shows that people who keep food diaries lose more weight than people who don’t.

2. Control your environment

This is absolutely crucial. It’s hard to eat something that isn’t there. On the other hand, if it’s sitting in front of you, it can be hard to resist, even if you didn’t want it to begin with.

Clear your home and office of unnecessary temptation. You can still eat treats, but it has to be a deliberate decision and not just because it was there.

3. Everything in (Individualised) Moderation

One of the twins said he was going to cut out all fat/sugar snacks. Sounds good in principle, but very difficult to do in practice. And let’s not forget (something that most doctors would be wise to acknowledge) some people don’t want to!

The key here is what I call “individualised moderation”. You don’t have to eliminate all snacks. That might be unpleasant. And if it’s unpleasant, most people won’t stick to it.

There will actually be some snacks that YOU can eat that make you happy and you’re able to eat them in moderation (which other people can’t). There are other foods (I call them danger foods) which you can’t be so restrained with.

This isn’t as simple as saying all 50:50 fat/ sugar foods are bad. It will be different for different people. And this is where the challenge comes in, because it takes some focus and effort (and trial and error) to discover what works for you.

4. Make Small Changes

Most diets push the line of thinking that to lose weight and be healthier, you have to make drastic changes to your diet. It almost seems virtuous to overhaul your eating. But this sort of wholesale change is difficult to implement. It’s almost like everything needs to be perfect (and quiet) in your life to stick to a diet. For most people, at the first sign of a work crisis, family problems, illness etc, they revert to their old lifestyle.

It’s much better to make gradual changes over time and create habits that you’re happy doing for the rest of your life.

The corollary of this is : don’t make big changes that you know you’re unlikely to stick to for more than a few days or weeks.

5. Patience

Changing your diet is a long-term undertaking. And it will generally take longer to achieve your goal than you thought it would (sorry). If you are impatient for results, you will second-guess yourself and undermine your progress. In my experience impatience for results is the number one reason people give up on their weight loss efforts.

6. Never give up.

You can only fail to lose weight if you give up. This is hard, because along the way there will be times when your weight doesn’t budge, times when you eat more than you intended, and times when your weight actually goes up.

Based in London’s Harley Street, Dr. K helps women over 40 lose weight without dieting or deprivation using a behaviour-focused weight loss approach. He is also the author of the Amazon bestsellers: “Slim and Healthy without Dieting" and "Losing Weight After 40".